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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2009 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: UTF8.html 16 2014-02-13 19:56:57Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.dellroad.lzma.client;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>/**<a name="line.10"></a>
<span class="sourceLineNo">011</span> * Encodes and decodes strings to/from binary using "modified UTF-8 encoding".<a name="line.11"></a>
<span class="sourceLineNo">012</span> * This is the same encoding as is used by Java class files.<a name="line.12"></a>
<span class="sourceLineNo">013</span> */<a name="line.13"></a>
<span class="sourceLineNo">014</span>public final class UTF8 {<a name="line.14"></a>
<span class="sourceLineNo">015</span><a name="line.15"></a>
<span class="sourceLineNo">016</span>    private UTF8() {<a name="line.16"></a>
<span class="sourceLineNo">017</span>    }<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>    /**<a name="line.19"></a>
<span class="sourceLineNo">020</span>     * Encode the given string.<a name="line.20"></a>
<span class="sourceLineNo">021</span>     */<a name="line.21"></a>
<span class="sourceLineNo">022</span>    public static byte[] encode(String s) {<a name="line.22"></a>
<span class="sourceLineNo">023</span>        final char[] chars = s.toCharArray();<a name="line.23"></a>
<span class="sourceLineNo">024</span>        int elen;<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>        // Compute encoded length<a name="line.26"></a>
<span class="sourceLineNo">027</span>        elen = 0;<a name="line.27"></a>
<span class="sourceLineNo">028</span>        for (int i = 0; i &lt; s.length(); i++) {<a name="line.28"></a>
<span class="sourceLineNo">029</span>            int ch = chars[i];<a name="line.29"></a>
<span class="sourceLineNo">030</span>            if (ch &gt;= 0x0001 &amp;&amp; ch &lt;= 0x007f)<a name="line.30"></a>
<span class="sourceLineNo">031</span>                elen++;<a name="line.31"></a>
<span class="sourceLineNo">032</span>            else if (ch == 0x0000 || (ch &gt;= 0x0080 &amp;&amp; ch &lt;= 0x07ff))<a name="line.32"></a>
<span class="sourceLineNo">033</span>                elen += 2;<a name="line.33"></a>
<span class="sourceLineNo">034</span>            else<a name="line.34"></a>
<span class="sourceLineNo">035</span>                elen += 3;<a name="line.35"></a>
<span class="sourceLineNo">036</span>        }<a name="line.36"></a>
<span class="sourceLineNo">037</span><a name="line.37"></a>
<span class="sourceLineNo">038</span>        // Do the actual encoding<a name="line.38"></a>
<span class="sourceLineNo">039</span>        byte[] data = new byte[elen];<a name="line.39"></a>
<span class="sourceLineNo">040</span>        elen = 0;<a name="line.40"></a>
<span class="sourceLineNo">041</span>        for (int i = 0; i &lt; s.length(); i++) {<a name="line.41"></a>
<span class="sourceLineNo">042</span>            int ch = chars[i];<a name="line.42"></a>
<span class="sourceLineNo">043</span>            if (ch &gt;= 0x0001 &amp;&amp; ch &lt;= 0x007f)<a name="line.43"></a>
<span class="sourceLineNo">044</span>                data[elen++] = (byte)ch;<a name="line.44"></a>
<span class="sourceLineNo">045</span>            else if (ch == 0x0000<a name="line.45"></a>
<span class="sourceLineNo">046</span>                || (ch &gt;= 0x0080 &amp;&amp; ch &lt;= 0x07ff)) {<a name="line.46"></a>
<span class="sourceLineNo">047</span>                data[elen++]<a name="line.47"></a>
<span class="sourceLineNo">048</span>                    = (byte)(0xc0 | ((ch &gt;&gt; 6) &amp; 0x1f));<a name="line.48"></a>
<span class="sourceLineNo">049</span>                data[elen++] = (byte)(0x80 | (ch &amp; 0x3f));<a name="line.49"></a>
<span class="sourceLineNo">050</span>            } else {<a name="line.50"></a>
<span class="sourceLineNo">051</span>                data[elen++]<a name="line.51"></a>
<span class="sourceLineNo">052</span>                    = (byte)(0xe0 | ((ch &gt;&gt; 12) &amp; 0x0f));<a name="line.52"></a>
<span class="sourceLineNo">053</span>                data[elen++]<a name="line.53"></a>
<span class="sourceLineNo">054</span>                    = (byte)(0x80 | ((ch &gt;&gt; 6) &amp; 0x3f));<a name="line.54"></a>
<span class="sourceLineNo">055</span>                data[elen++] = (byte)(0x80 | (ch &amp; 0x3f));<a name="line.55"></a>
<span class="sourceLineNo">056</span>            }<a name="line.56"></a>
<span class="sourceLineNo">057</span>        }<a name="line.57"></a>
<span class="sourceLineNo">058</span>        return data;<a name="line.58"></a>
<span class="sourceLineNo">059</span>    }<a name="line.59"></a>
<span class="sourceLineNo">060</span><a name="line.60"></a>
<span class="sourceLineNo">061</span>    /**<a name="line.61"></a>
<span class="sourceLineNo">062</span>     * Decode the given UTF-8 data.<a name="line.62"></a>
<span class="sourceLineNo">063</span>     *<a name="line.63"></a>
<span class="sourceLineNo">064</span>     * @throws IllegalArgumentException if the UTF-8 input is invalid<a name="line.64"></a>
<span class="sourceLineNo">065</span>     */<a name="line.65"></a>
<span class="sourceLineNo">066</span>    public static String decode(byte[] utf) {<a name="line.66"></a>
<span class="sourceLineNo">067</span>        StringBuilder buf = new StringBuilder(utf.length);<a name="line.67"></a>
<span class="sourceLineNo">068</span>        for (int i = 0; i &lt; utf.length; i++) {<a name="line.68"></a>
<span class="sourceLineNo">069</span>            int x = utf[i] &amp; 0xff;<a name="line.69"></a>
<span class="sourceLineNo">070</span>            if ((x &amp; 0x80) == 0) {<a name="line.70"></a>
<span class="sourceLineNo">071</span>                if (x == 0)<a name="line.71"></a>
<span class="sourceLineNo">072</span>                    throw new IllegalArgumentException("invalid UTF-8");<a name="line.72"></a>
<span class="sourceLineNo">073</span>                buf.append((char)x);<a name="line.73"></a>
<span class="sourceLineNo">074</span>            } else if ((x &amp; 0xe0) == 0xc0) {<a name="line.74"></a>
<span class="sourceLineNo">075</span>                if (i + 1 &gt;= utf.length)<a name="line.75"></a>
<span class="sourceLineNo">076</span>                    throw new IllegalArgumentException("invalid UTF-8");<a name="line.76"></a>
<span class="sourceLineNo">077</span>                int y = utf[++i] &amp; 0xff;<a name="line.77"></a>
<span class="sourceLineNo">078</span>                if ((y &amp; 0xc0) != 0x80)<a name="line.78"></a>
<span class="sourceLineNo">079</span>                    throw new IllegalArgumentException("invalid UTF-8");<a name="line.79"></a>
<span class="sourceLineNo">080</span>                buf.append((char)(((x &amp; 0x1f) &lt;&lt; 6) | (y &amp; 0x3f)));<a name="line.80"></a>
<span class="sourceLineNo">081</span>            } else if ((x &amp; 0xf0) == 0xe0) {<a name="line.81"></a>
<span class="sourceLineNo">082</span>                if (i + 2 &gt;= utf.length)<a name="line.82"></a>
<span class="sourceLineNo">083</span>                    throw new IllegalArgumentException("invalid UTF-8");<a name="line.83"></a>
<span class="sourceLineNo">084</span>                int y = utf[++i] &amp; 0xff;<a name="line.84"></a>
<span class="sourceLineNo">085</span>                if ((y &amp; 0xc0) != 0x80)<a name="line.85"></a>
<span class="sourceLineNo">086</span>                    throw new IllegalArgumentException("invalid UTF-8");<a name="line.86"></a>
<span class="sourceLineNo">087</span>                int z = utf[++i] &amp; 0xff;<a name="line.87"></a>
<span class="sourceLineNo">088</span>                if ((z &amp; 0xc0) != 0x80)<a name="line.88"></a>
<span class="sourceLineNo">089</span>                    throw new IllegalArgumentException("invalid UTF-8");<a name="line.89"></a>
<span class="sourceLineNo">090</span>                buf.append((char)(((x &amp; 0x0f) &lt;&lt; 12) | ((y &amp; 0x3f) &lt;&lt; 6) | (z &amp; 0x3f)));<a name="line.90"></a>
<span class="sourceLineNo">091</span>            } else<a name="line.91"></a>
<span class="sourceLineNo">092</span>                throw new IllegalArgumentException("invalid UTF-8");<a name="line.92"></a>
<span class="sourceLineNo">093</span>        }<a name="line.93"></a>
<span class="sourceLineNo">094</span>        return buf.toString();<a name="line.94"></a>
<span class="sourceLineNo">095</span>    }<a name="line.95"></a>
<span class="sourceLineNo">096</span><a name="line.96"></a>
<span class="sourceLineNo">097</span>    public static void main(String[] args) throws Exception {<a name="line.97"></a>
<span class="sourceLineNo">098</span>        for (String arg : args) {<a name="line.98"></a>
<span class="sourceLineNo">099</span>            final byte[] utf = UTF8.encode(arg);<a name="line.99"></a>
<span class="sourceLineNo">100</span>            StringBuilder buf = new StringBuilder(utf.length * 2);<a name="line.100"></a>
<span class="sourceLineNo">101</span>            for (byte b : utf) {<a name="line.101"></a>
<span class="sourceLineNo">102</span>                int val = b &amp; 0xff;<a name="line.102"></a>
<span class="sourceLineNo">103</span>                buf.append(Integer.toHexString(val &gt;&gt; 4));<a name="line.103"></a>
<span class="sourceLineNo">104</span>                buf.append(Integer.toHexString(val &amp; 0xf));<a name="line.104"></a>
<span class="sourceLineNo">105</span>            }<a name="line.105"></a>
<span class="sourceLineNo">106</span>            System.out.println("encode(\"" + arg + "\") = " + buf);<a name="line.106"></a>
<span class="sourceLineNo">107</span>            System.out.println("decode(" + buf + ") = \"" + UTF8.decode(utf) + "\"");<a name="line.107"></a>
<span class="sourceLineNo">108</span>        }<a name="line.108"></a>
<span class="sourceLineNo">109</span>    }<a name="line.109"></a>
<span class="sourceLineNo">110</span>}<a name="line.110"></a>
<span class="sourceLineNo">111</span><a name="line.111"></a>




























































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